T o date, hundreds of thousands of deaths have been attributed to coronavirus disease 2019 (COVID-19) 1. Millions of infections by SARS-CoV-2, the virus responsible for COVID-19, have been reported, although its full extent has yet to be determined owing to limited testing 2. Government interventions to slow viral spread have disrupted daily life and economic activity for billions of people. Strategies to ease restraints on human mobility and interaction without provoking a major resurgence of transmission and mortality will depend on accurate estimates of population levels of infection and immunity 3. Current testing for the virus largely depends on labor-intensive molecular techniques 4. Individuals with positive molecular tests represent only a small fraction of all infections, given limited deployment and the brief time window when real-time (RT)-PCR testing has the highest sensitivity 5-7. The proportion of undocumented cases in the original epidemic focus was estimated to be as high as 86% 8 , and asymptomatic infections are suspected to play a substantial role in transmission 9-14. Widely available, reliable antibody detection assays would enable more accurate estimates of SARS-CoV-2 prevalence and incidence. On February 4, 2020, the Secretary of the US Department of Health and Human Services issued an emergency use authorization (EUA) for the diagnosis of SARS-CoV-2 15 , allowing nucleic acid detection and immunoassay tests to be offered based on manufacturer-reported data without formal US Food and Drug Administration (FDA) clearance 16. In response, dozens of companies began to market laboratory-based immunoassays and point-of-care (POC) tests. Rigorous, comparative performance data are crucial to inform clinical care and public health responses.

Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key for understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active phosphotyrosine-containing proteins by genetically encoding a stable phosphotyrosine analogue that is convertible into native phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, phosphotyrosine site and function, and reveal a possible negative regulation role of tyrosine phosphorylation in ubiquitination.

Ubiquitin is essential for eukaryotic life and varies in only 3 amino acid positions between yeast and humans. However, recent deep sequencing studies indicate that ubiquitin is highly tolerant to single mutations. We hypothesized that this tolerance would be reduced by chemically induced physiologic perturbations. To test this hypothesis, a class of first year UCSF graduate students employed deep mutational scanning to determine the fitness landscape of all possible single residue mutations in the presence of five different small molecule perturbations. These perturbations uncover 'shared sensitized positions' localized to areas around the hydrophobic patch and the C-terminus. In addition, we identified perturbation specific effects such as a sensitization of His68 in HU and a tolerance to mutation at Lys63 in DTT. Our data show how chemical stresses can reduce buffering effects in the ubiquitin proteasome system. Finally, this study demonstrates the potential of lab-based interdisciplinary graduate curriculum.DOI: http://dx.doi.org/10.7554/eLife.15802.001

Background: Pasteurella multocida toxin (PMT) is a highly mitogenic bacterial protein whose detailed mechanism is not well understood. Results: PMT deamidates and activates G␣ q/11 leading to mTORC1 activation. Conclusion: G␣ q/11 /PLC␤/PKC-mediated mTORC1 activation is at least partially responsible for PMT-induced cell growth, migration, and proliferation in Swiss 3T3 cells. Significance: Understanding PMT-induced mTORC1 activation could help elucidate mechanisms of oncogene regulation.